Proton Pumping Activity Research Articles

Inhibitory protonové pumpy – známe je dobře? Jsou skutečně tak bezpečné? – část 1

Proton pump inhibitors (PPIs) are one of the most commonly used drug groups. More than 10% of patients being chronically treated in the adult population. Often patients with a high risk of vascular or renal impairment. In addition to the unquestionable effect in the treatment and in the prophylaxis of gastroduodenal diseases, PPIs have been promoted in combination with antithrombotic therapy in order to reduce bleeding in the gastrointestinal tract. In both of these indications, this is a chronic treatment, often for several years. Drug regulatory agencies (EMAs or FDA) warn against chronic PPIs use, warning of a number of serious side effects. However, chronic administration of PPIs is a common practice. It is therefore time to evaluate the benefit and risk of this important drug group. First of all, it should be noted that PPIs operate not only at the level of the classical gastric proton pump (H+/K+ ATPase), but also block the activity of the sister vacuolar proton pump (V-H+-ATPase) in a number of other organs or organelles, namely lysosomes of all somatic cells. Similarly, PPIs block the activity of a number of transporters and metabolic enzymes. Action at this level is likely to surprise the gastroenterologist. There is no doubt about the benefits of PPIs in the indication of treatment and prevention of ulcerative or reflux disease. However, what are the evidence to reduce the risk of gastriontestinal bleeding in antithrombotic treatment? In this area we have data at the level of observational studies, the decrease in the risk of bleeding by about a third is significant. However, with a relatively low incidence of bleeding in the gastrointestinal tract, the absolute decrease in risk is small, hovering at 0.3%. The observed number need to treat is around 250, i.e. for every 250 PPIs treated, we will prevent one bleeding (usually not critical). On the other hand, there are increasingly work that finds a higher incidence of cardiovascular events, renal failure, bronchial asthma and nervous disabilities in chronic PPIs treatment. In a population at high cardiovascular risk, i.e. in a typical population where we add antithrombotic treatment to PPIs, the risk is significant. The number need to harm value is around 50. Thus, in the chronic use of PPIs, the risk outweighs the benefit.

NaCl-altered oxygen flux profiles and H+-ATPase activity in roots of two contrasting poplar species.

Maintaining mitochondrial respiration is crucial for proving ATP for H+ pumps to continuously exclude Na+ under salt stress. NaCl-altered O2 uptake, mitochondrial respiration and the relevance to H+-ATPase activity were investigated in two contrasting poplar species, Populus euphratica (salt-tolerant) and Populus popularis 35-44 (salt-sensitive). Compared with P. popularis, P. euphratica roots exhibited a greater capacity to extrude Na+ under NaCl stress (150mM). The cytochemical analysis with Pb(NO3)2 staining revealed that P. euphratica root cells retained higher H+ hydrolysis activity than the salt-sensitive poplar during a long term (LT) of increasing salt stress (50-200mM NaCl, 4weeks). Long-sustained activation of proton pumps requires long-lasting supply of energy (adenosine triphosphate, ATP), which is delivered by aerobic respiration. Taking advantage of the vibrating-electrodes technology combined with the use of membrane-tipped, polarographic oxygen microelectrodes, the species, spatial and temporal differences in root O2 uptake were characterized under conditions of salt stress. Oxygen uptake upon NaCl shock (150mM) was less declined in P. euphratica than in P. popularis, although the salt-induced transient kinetics were distinct from the drastic drop of O2 caused by hyperosmotic shock (255mM mannitol). Short-term (ST) treatment (150mM NaCl, 24h) stimulated O2 influx in P. euphratica roots, and LT-treated P. euphratica displayed an increased O2 influx along the root axis, whereas O2 influx declined with increasing salinity in P. popularis roots. The spatial localization of O2 influxes revealed that the apical zone was more susceptible than the elongation region upon high NaCl (150, 200mM) during ST and LT stress. Pharmacological experiments showed that the Na+ extrusion and H+-ATPase activity in salinized roots were correspondingly suppressed when O2 uptake was inhibited by a mitochondrial respiration inhibitor, NaN3. Therefore, we conclude that the stable mitochondrial respiration energized H+-ATPase of P. euphratica root cells for maintaining Na+ homeostasis under salt environments.

Recent advances in bacteriorhodopsin-based energy harvesters and sensing devices

Bacteriorhodopsin (bR) is a trans-membrane photoactive protein commonly found in the purple membrane of Halobacterium salinarum . In light of the enhanced potential for light-activated proton pumping and color switching, this protein has been adopted favorably as platforms for versatile applications such as solar cells, fuel cells, biosensors, artificial retinas, optical devices, nanosensors, storage devices, camouflage, bio-defense, holographic memory, and security ink. This review is organized to highlight the photocycle of bR which can be modified through mutation. Because of high stability and proton-release characteristics, bR is regarded as an attractive platform for the production of hydrogen through the splitting of water to help maintain a sustainable economy based on renewable energy. In this review, recent advances in bR-based hybrid electrodes are summarized for their applications toward solar cells, water-splitting devices, and fuel cells. Further, emerging applications of bR in sensors and security inks are also discussed to apprise researchers of the potential and challenges in bR research. • Bacteriorhodopsin is a purple membrane and light activated proton pumping protein. • Engineering of bR photocycle and its role are discussed with respect to proton pumping activity. • bR-based hybrid electrodes are efficient alternate for sensors, solar/fuel cells, and HER. • Future prospects of bR are addressed in energy, sensing, and information encryption.

Inoculation with the endophytic bacterium Herbaspirillum seropedicae promotes growth, nutrient uptake and photosynthetic efficiency in rice.

Higher vacuolar proton pump activity may increase plant energy and nutrient use efficiency and provide the nexus between plant inoculation with Herbaspirillum seropedicae and growth promotion. Global change and growing human population are exhausting arable land and resources, including water and fertilizers. We present inoculation with the endophytic plant-growth promoting bacterium (PGPB) Herbaspirillum seropedicae as a strategy for promoting growth, nutrient uptake and photosynthetic efficiency in rice (Oryza sativa L.). Because plant nutrient acquisition is coordinated with photosynthesis and the plant carbon status, we hypothesize that inoculation with H. seropedicae will stimulate proton (H+) pumps, increasing plant growth nutrient uptake and photosynthetic efficiency at low nutrient levels. Plants were inoculated and grown in pots with sterile soil for 90days. Herbaspirillum seropedicae endophytic colonization was successful and, as hypothesized, inoculation (1) stimulated root vacuolar H+ pumps (vacuolar H+-ATPase and vacuolar H+-PPase), and (2) increased plant growth, nutrient contents and photosynthetic efficiency. The results showed that inoculation with the endophytic bacterium H. seropedicae can promote plant growth, nutrient uptake and photosynthetic efficiency, which will likely result in a more efficient use of resources (nutrients and water) and higher production of nutrient-rich food at reduced economic and environmental costs.

COMPARATIVE EVALUATION OF ROOT CANAL DISINFECTION USING 3% SODIUM HYPOCHLORITE, 940NM DIODE LASER AND PHOTODYNAMIC THERAPY IN SINGLE SITTING PULPECTOMY: AN IN-VIVO STUDY

Introduction: Enterococcus faecalis is a common bacterial species in resistant and recurrent infections. It has an active proton pump which prevents its easy inhibition leading to endodontic treatment failure. LASER and photodynamic therapy have been employed lately in improving antimicrobial chemotherapy of localized infections. Aim: To compare disinfection efficacy of 940nm Diode LASER & Photodynamic therapy(PDT) to Conventional method using 3% Sodium hypochlorite in canals of endodontically treated primary teeth. Method: Single sitting Pulpectomy was performed on 60 mandibular first primary molars, divided into 3 groups, disinfected using mentioned modalities. Disinfection potential was compared collecting samples at 3 stages using paper points, cultured and incubated for 24hrs to check change in Colony Forming Units of the bacteria. Results: Data analysis with SPSS version 20 software using Kruskal-Wallis and Mann Whitney-U test. Conclusion: The three groups showed effective disinfection as revealed by the reduction in the colony forming units of the bacteria at baseline and after intervention. However, diode laser when used in conjunction with sodium hypochlorite as a disinfecting modality was found to be the most effective for the eradication of Enterococcus faecalis from infected root canals.

In vivo anti-V-ATPase antibody treatment delays ovarian tumor growth by increasing antitumor immune responses.

Tumor acidity is the key metabolic feature promoting cancer progression and is modulated by pH regulators on a cancer cell's surface that pump out excess protons/lactic acid for cancer cell survival. Neutralizing tumor acidity improves the therapeutic efficacy of current treatments including immunotherapies. Vacuolar-ATPase (V-ATPase) proton pumps encompass unique plasma membrane-associated subunit isoforms, making this molecule an important target for anticancer therapy. Here, we examined the invivo therapeutic efficacy of an antibody (a2v-mAB) targeting specific V-ATPase-'V0a2' surface isoform in controlling ovarian tumor growth. Invitro a2v-mAb treatment inhibited the proton pump activity in ovarian cancer (OVCA) cells. Invivo intraperitoneal a2v-mAb treatment drastically delayed ovarian tumor growth with no measurable invivo toxicity in a transplant tumor model. To explore the possible mechanism causing delayed tumor growth, histochemical analysis of the a2v-mAb-treated tumor tissues displayed high immune cell infiltration (M1-macrophages, neutrophils, CD103+ cells, and NK cells) and an enhanced antitumor response (iNOS, IFN-y, IL-1α) compared to control. There was marked decrease in CA-125-positive cancer cells and an enhanced active caspase-3 expression in a2v-mAb-treated tumors. RNA-seq analysis of a2v-mAb tumor tissues further revealed upregulation of apoptosis-related and toll-like receptor pathway-related genes. Indirect coculture of a2v-mAb-treated OVCA cells with human PBMCs in an unbuffered medium led to an enhanced gene expression of antitumor molecules IFN-y, IL-17, and IL-12-A in PBMCs, further validating the invivo antitumor responses. In conclusion, V-ATPase inhibition using a monoclonal antibody directed against the V0a2 isoform increases antitumor immune responses and could therefore constitute an effective treatment strategy in OVCA.

Novel insights into the calcium action in cherry fruit development revealed by high-throughput mapping.

This work provides the first system-wide datasets concerning metabolic changes in calcium-treated fruits, which reveal that exogenously applied calcium may specifically reprogram sweet cherry development and ripening physiognomy. Calcium modulates a wide range of plant developmental processes; however, the regulation of fruit ripening by calcium remains largely uncharacterized. In this study, transcriptome, proteome and metabolome profiling was used to document the responses of sweet cherry fruit to external calcium application (0.5% CaCl2) at 15, 27 and 37days after full blossom. Endogenous calcium loading in fruit across development following external calcium feeding was accompanied by a reduction in respiration rate. Calcium treatment strongly impaired water-induced fruit cracking tested by two different assays, and this effect depended on the fruit size, water temperature and light/dark conditions. Substantial changes in the levels of numerous polar/non-polar primary and secondary metabolites, including malic acid, glucose, cysteine, epicatechin and neochlorogenic acid were noticed in fruits exposed to calcium. At the onset of ripening, we identified various calcium-affected genes, including those involved in ubiquitin and cysteine signaling, that had not been associated previously with calcium function in fruit biology. Calcium specifically increased the abundance of a significant number of proteins that classified as oxidoreductases, transferases, hydrolases, lyases, and ligases. The overview of temporal changes in gene expression and corresponding protein abundance provided by interlinked analysis revealed that oxidative phosphorylation, hypersensitive response, DNA repair, stomata closure, biosynthesis of secondary metabolites, and proton-pump activity were mainly affected by calcium. This report provides the fullest characterization of expression patterns in calcium-responsive genes, proteins and metabolites currently available in fruit ripening and will serve as a blueprint for future biological endeavors.

Dynamics of Bacteriorhodopsin in the Dark‐Adapted State from Solution Nuclear Magnetic Resonance Spectroscopy

AbstractTo achieve efficient proton pumping in the light‐driven proton pump bacteriorhodopsin (bR), the protein must be tightly coupled to the retinal to rapidly convert retinal isomerization into protein structural rearrangements. Methyl group dynamics of bR embedded in lipid nanodiscs were determined in the dark‐adapted state, and were found to be mostly well ordered at the cytosolic side. Methyl groups in the M145A mutant of bR, which displays only 10 % residual proton pumping activity, are less well ordered, suggesting a link between side‐chain dynamics on the cytosolic side of the bR cavity and proton pumping activity. In addition, slow conformational exchange, attributed to low frequency motions of aromatic rings, was indirectly observed for residues on the extracellular side of the bR cavity. This may be related to reorganization of the water network. These observations provide a detailed picture of previously undescribed equilibrium dynamics on different time scales for ground‐state bR.

Dynamics of Bacteriorhodopsin in the Dark‐Adapted State from Solution Nuclear Magnetic Resonance Spectroscopy

To achieve efficient proton pumping in the light-driven proton pump bacteriorhodopsin (bR), the protein must be tightly coupled to the retinal to rapidly convert retinal isomerization into protein structural rearrangements. Methyl group dynamics of bR embedded in lipid nanodiscs were determined in the dark-adapted state, and were found to be mostly well ordered at the cytosolic side. Methyl groups in the M145A mutant of bR, which displays only 10 % residual proton pumping activity, are less well ordered, suggesting a link between side-chain dynamics on the cytosolic side of the bR cavity and proton pumping activity. In addition, slow conformational exchange, attributed to low frequency motions of aromatic rings, was indirectly observed for residues on the extracellular side of the bR cavity. This may be related to reorganization of the water network. These observations provide a detailed picture of previously undescribed equilibrium dynamics on different time scales for ground-state bR.

Attenuation of ischemia-reperfusion-induced gastric ulcer by low-dose vanadium in male Wistar rats

AimVanadium, a trace element found in food and water sources has been previous reported to attenuate ulcer formation without much insight into its mechanism of action. This study highlights the mechanism by which vanadium exhibits its gastro-protective activity. Main methodsEighty male Wistar rats (80–100 g) were randomized into 8 equal groups. Groups 1 (control) and 2 (Ulcerated control) received water only, groups 3–8 received vanadium at 5, 10, 25, 50, 100 and 200 ppm respectively in their drinking water for ten weeks. Gastric ulcer was thereafter induced in groups (2–8) via ischaemia-reperfusion (IR) technique. The stomachs were excised for macroscopic examination, evaluation of mucous content, oxidative stress markers, hydrogen/potassium (H+/K+) and calcium (Ca++) ATPases activities plus expression of induced nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2). Vanadium at low doses inhibited IR induced gastric ulcer by 62.62% (10 ppm), 54.80% (25 ppm) and 43.50% (50 ppm). Key findingsLow dose vanadium increased mucous content, superoxide dismutase, catalase, glutathione activities and nitrite concentrations compared to ulcerated control group. The observed increase in malondialdehyde, Ca++ and H+/K+ ATPase activities, iNOS and COX-2 expression following IR were significantly reduced by pretreatment with vanadium. SignificanceThis study demonstrated that vanadium at low doses exhibit gastro-protective activities on IR induced gastric ulcer in rat model by inhibiting proton pump activities and decreasing expressions of iNOS and COX-2, thereby giving more insight into the protective action of vanadium.

Reducing the Nitrate Content in Vegetables Through Joint Regulation of Short-Distance Distribution and Long-Distance Transport.

As an important nitrogen source, nitrate (NO3−) absorbed by plants is carried throughout the plant via short-distance distribution (cytoplasm to vacuole) and long-distance transportation (root to shoot), the two pathways that jointly regulate the content of NO3− in plants. NO3− accumulation within the vacuole depends on the activities of both tonoplast proton pumps and chloride channel (CLC) proteins, and less NO3− is stored in vacuoles when the activities of these proteins are reduced. The ratio of the distribution of NO3− in the cytoplasm and vacuole affects the long-distance transport of NO3−, which is regulated by the proteins NPF7.3 and NPF7.2 that play opposite but complementary roles. NPF7.3 is responsible for loading NO3− from the root cytoplasm into the xylem, whereas NPF7.2 regulates the unloading of NO3− from the xylem, thereby facilitating the long-distance transport of NO3− through the roots to the shoots. Vegetables, valued for their nutrient content, are consumed in large quantities; however, a high content of NO3− can detrimentally affect the quality of these plants. NO3− that is not assimilated and utilized in plant tissues is converted via enzyme-catalyzed reactions to nitrite (NO2−), which is toxic to plants and harmful to human health. In this review, we describe the mechanisms underlying NO3− distribution and transport in plants, a knowledge of which will contribute to breeding leafy vegetables with lower NO3− contents and thus be of considerable significance from the perspectives of environmental protection and food safety.

Susceptibility of the Formate Hydrogenlyase Reaction to the Protonophore CCCP Depends on the Total Hydrogenase Composition

Fermentative hydrogen production by enterobacteria derives from the activity of the formate hydrogenlyase (FHL) complex, which couples formate oxidation to H2 production. The molybdenum-containing formate dehydrogenase and type-4 [NiFe]-hydrogenase together with three iron-sulfur proteins form the soluble domain, which is attached to the membrane by two integral membrane subunits. The FHL complex is phylogenetically related to respiratory complex I, and it is suspected that it has a role in energy conservation similar to the proton-pumping activity of complex I. We monitored the H2-producing activity of FHL in the presence of different concentrations of the protonophore CCCP. We found an inhibition with an apparent EC50 of 31 µM CCCP in the presence of glucose, a higher tolerance towards CCCP when only the oxidizing hydrogenase Hyd-1 was present, but a higher sensitivity when only Hyd-2 was present. The presence of 200 mM monovalent cations reduced the FHL activity by more than 20%. The Na+/H+ antiporter inhibitor 5-(N-ethyl-N-isopropyl)-amiloride (EIPA) combined with CCCP completely inhibited H2 production. These results indicate a coupling not only between Na+ transport activity and H2 production activity, but also between the FHL reaction, proton import and cation export.

Phyllotaxis Turns Over a New Leaf-A New Hypothesis.

Phyllotaxis describes the periodic arrangement of plant organs most conspicuously floral. Oscillators generally underlie periodic phenomena. A hypothetical algorithm generates phyllotaxis regulated by the Hechtian growth oscillator of the stem apical meristem (SAM) protoderm. The oscillator integrates biochemical and mechanical force that regulate morphogenetic gradients of three ionic species, auxin, protons and Ca2+. Hechtian adhesion between cell wall and plasma membrane transduces wall stress that opens Ca2+ channels and reorients auxin efflux “PIN” proteins; they control the auxin-activated proton pump that dissociates Ca2+ bound by periplasmic arabinogalactan proteins (AGP-Ca2+) hence the source of cytosolic Ca2+ waves that activate exocytosis of wall precursors, AGPs and PIN proteins essential for morphogenesis. This novel approach identifies the critical determinants of an algorithm that generates phyllotaxis spiral and Fibonaccian symmetry: these determinants in order of their relative contribution are: (1) size of the apical meristem and the AGP-Ca2+ capacitor; (2) proton pump activity; (3) auxin efflux proteins; (4) Ca2+ channel activity; (5) Hechtian adhesion that mediates the cell wall stress vector. Arguably, AGPs and the AGP-Ca2+ capacitor plays a decisive role in phyllotaxis periodicity and its evolutionary origins.

Reduced Plasma Membrane H+-ATPase Isoform OsA7 Expression and Proton Pump Activity Decrease Growth Without Affecting Nitrogen Accumulation in Rice

Plasma membrane H+-ATPase (PM H+-ATPase, EC 3.6.1.3.) is a proton pump that is necessary to promote cell growth and ion fluxes across the plasma membrane. The main goal of this study was to evaluate the role of PM H+-ATPase isoform OsA7 expression in rice growth and nitrogen (N) accumulation using three genetically engineered lineages with artificial micro RNA (amiRNA) targeting OsA7 (osa7.1, osa7.2, and osa7.3). PM H+-ATPase isoform expression in rice shoots and roots (wild-type) revealed that OsA7 is highly expressed in roots and is the most highly expressed PM H+-ATPase isoform. The three osa7 lineages had lower fresh weight, grain yield, height, and 1000-grain weight compared to control IRS plants. The hydroponic experiment comprised three NO3− levels over 30 days: 0.2 mM NO3−–N, 2.0 mM NO3−–N, and NO3− starvation for 3 days. The three osa7 lineages had lower PM H+-ATPase and V-H+-PPase activity as compared to the IRS plants. The root and shoot fresh weights were lower in osa7 lineages. The root/shoot ratio was lower in the osa7 lineages cultivated without nitrogen for 3 days and with 0.2 mM of NO3−–N as compared to IRS, and did not change in plants cultivated with 2.0 mM NO3−–N. The total N concentration did not change in the three osa7 lineages as compared to IRS. Overall, the results indicate that OsA7 is important for rice growth, grain production, and root growth, but does not affect N accumulation, highlighting the importance of other PM H+-ATPase isoforms in N uptake.

Reconstitution of Respiratory Enzymes in PDMS-g-PEO Polymer and Polymer/Lipid Hybrid Vesicles

Mechanical characteristics (e.g. rigidity, tightness) of cellular compartments are alterable by partial or complete replacement of natural building blocks with synthetic alternatives, but often at the expense of other properties (e.g. fluidity, thickness). Since the scope of bottom-up synthetic biology aims to reconstitute essential life processes such as selective transport and energy transduction, we seek to retain properties of the interfaces, necessary for interaction with membrane proteins. PDMS-g-PEO polymer appears to accommodate these demands. Thus, we co-reconstituted the chemically-driven proton pump bo3 oxidase and F1Fo-ATPase in PDMS-g-PEO polymer and hybrid nanocompartments (LUVs) in order to build a synthetic energy conversion module. Successful scale-up to the micron-scale plays a crucial role in the real-time visualization and characterization of this module. Via an optimized fusion/electroformation approach we integrated bo3 oxidase in giant vesicles (GUVs) and determined its influence on mechanical properties. The reconstituted enzymes had preserved activity and exhibited unidirectional orientation, which led to the acidification of the synthetic compartments. The most remarkable finding is that the characteristics of hybrid membranes are not always intermediate between pure lipid- and pure polymer ones. Blending led to increased permeability, but after inserting the proton pump the compartments were surprisingly re-sealed. The measurements of active proton pumping and passive proton permeability were done in a microfluidic setup, which enabled monitoring of individual GUVs as well as better control of the experimental conditions. Moreover, we observed an interesting phenomenon beneficial for crowded membranes: While insertion of bo3 oxidase in soy PC decreased the fluidity, it exercised the opposite effect on the polymer by loosening its structure. The F1Fo-GUVs were prepared by the aforementioned procedure and the enzymatic activity was analyzed via outward proton pumping. Finally, respiratory-driven energy-converting GUVs were constructed. Sponsored by BMBF and MPG.

Temperature Dependency of Proton Pumping Activity for Marine Microbial Rhodopsin from Antartic Ocean

Proteorhodopsin (PR) is discovered from marine bacteria and it has proton pumping activity from inside to outside of the cell using light energy. In general, PR classified into two groups by the maximum absorption spectra. In this study, we isolated the two of a full sequence of opsin homologues by PCR from the seawater sample near King George Island, Antarctica. One was the same sequence as the first reported GPR (Green-light absorbing PR) from Monterey Bay. Another named HSG119 was a newly discovered sequence which shows high sequence similarity with BPR (Blue-light absorbing PR). HSG119 has an absorption maximum at 493 nm with broader spectrum at pH7.0 and it can pump protons out of the cell membrane. Interestingly, it showed a similar temperature dependence to GPR(Y200N) that isolated near the North pole.

Evolutionary and Functional Analysis of a Chara Plasma Membrane H+-ATPase.

H+-ATPases are the main transporters in plant and fungal plasma membranes (PMs), comparable to the Na+/K+ ATPases in animal cells. At the molecular level, most studies on the PM H+-ATPases have been focused on land plants and fungi (yeast). The research of PM H+-ATPases in green algae falls far behind due to the lack of genetic information. Here we studied a potential PM H+-ATPase (CHA1) from Chara australis, a species of green algae belonging to the division Charophyta, members of which are considered to be one of the closest ancestors of land plants. The gene encodes a 107 kDa protein with all 6 P-type ATPase-specific motifs and a long, diverse C-terminal domain. A new amino acid sequence motif R*****Q in transmembrane segment 5 was identified among the known PM H+-ATPases from Charophyta and Chlorophyta algae, which is different from the typical PM H+-ATPases in yeast or land plants. Complementation analysis in yeast showed that CHA1 could successfully reach the PM, and that proton pump activity was obtained when the last 77 up to 87 amino acids of the C-terminal domain were deleted. PM localization was confirmed in Arabidopsis protoplasts; however, deletion of more than 55 amino acids at the N-terminus or more than 98 amino acids at the C-terminus resulted in failure of CHA1 to reach the PM in yeast. These results suggest that an auto-inhibition domain is located in the C-terminal domain, and that CHA1 is likely to have a different regulation mechanism compared to the yeast and land plant PM H+-ATPases.

Phytopharmacological Evaluation of Alcoholic Extract of Berberis aristata Leaf in the Treatment of Gastric Ulcer

For over a century, peptic ulcer has been one of the most common gastrointestinal tract (GIT) disorder. There are number of drugs are now available for treatment. Drugs of herbal origin reduce the offensive factors and have proved to be safe, clinically effective, relatively less expensive, globally competitive, and with better patient tolerance.This study was performed to assess the anti-ulcer activity on different parts of B.aristata. Apart from that, acute toxicity, qualitative chemical analysis, total phenolic content (TPC), total flavonoid content(TFC) and in vitro antioxidant activities were evaluated. The potentially active plant part was selected for screening as gastro protective, in vivo antioxidant and antisecretory activities in ulcerated rats.The 50% ethanolic extract of B. aristata were subjected to preliminary phytochemical screening, estimation of TFC and TPC. The crude extract from the leaves of B. aristata gave best antiulcer activity among flower and stem. In acute toxicity studies, the administration of the crude extract of B. aristata leaves did not reveal any adverse effects or toxicity in rats at fourteen days observations.The results of these studies have shown that ethylexract of B.aristata leaf (EEBAL) produced a significant dose dependent ulcerprotective, antioxidant and antisecretory activity by blocking the activity of proton pump, protecting from antioxidants produced during stress induced ulcer and by enhancing glycoprotein levels.

Salt-water acclimation of the estuarine crocodile Crocodylus porosus involves enhanced ion transport properties of the urodaeum and rectum.

Estuarine crocodiles, Crocodylus porosus, inhabit freshwater, estuarine and marine environments. Despite being known to undertake extensive movements throughout and between hypo-osmotic and hyperosmotic environments, little is known about the role of the cloaca in coping with changes in salinity. We report here that, in addition to the well-documented functional plasticity of the lingual salt glands, the middle of the three cloacal segments (i.e. the urodaeum) responds to increased ambient salinity to enhance solute-coupled water absorption. This post-renal modification of urine serves to conserve water when exposed to hyperosmotic environments and, in conjunction with lingual salt gland secretions, enables C. porosus to maintain salt and water balance and thereby thrive in hyperosmotic environments. Isolated epithelia from the urodaeum of 70% seawater-acclimated C. porosus had a strongly enhanced short-circuit current (an indicator of active ion transport) compared with freshwater-acclimated crocodiles. This enhanced active ion absorption was driven by increased Na+/K+-ATPase activity, and possibly enhanced proton pump activity, and was facilitated by the apical epithelial Na+ channel (ENaC) and/or the apical Na+/H+ exchanger (NHE2), both of which are expressed in the urodaeum. NHE3 was expressed at very low levels in the urodaeum and probably does not contribute to solute-coupled water absorption in this cloacal segment. As C. porosus does not appear to drink water of salinities above 18ppt, observations of elevated short-circuit current in the rectum as well as a trend for increased NHE2 expression in the oesophagus, the anterior intestine and the rectum suggest that dietary salt intake may stimulate salt and possibly water absorption by the gastrointestinal tract of C. porosus living in hyperosmotic environments.

Pathogen‐induced pH changes regulate the growth‐defense balance in plants

Environmental adaptation of organisms relies on fast perception and response to external signals, which lead to developmental changes. Plant cell growth is strongly dependent on cell wall remodeling. However, little is known about cell wall‐related sensing of biotic stimuli and the downstream mechanisms that coordinate growth and defense responses. We generated genetically encoded pH sensors to determine absolute pH changes across the plasma membrane in response to biotic stress. A rapid apoplastic acidification by phosphorylation‐based proton pump activation in response to the fungus Fusarium oxysporum immediately reduced cellulose synthesis and cell growth and, furthermore, had a direct influence on the pathogenicity of the fungus. In addition, pH seems to influence cellulose structure. All these effects were dependent on the COMPANION OF CELLULOSE SYNTHASE proteins that are thus at the nexus of plant growth and defense. Hence, our discoveries show a remarkable connection between plant biomass production, immunity, and pH control, and advance our ability to investigate the plant growth‐defense balance.